Millions of bitcoin investors in China are seeing their assets partly frozen, as three major bitcoin trading platforms in the country have suspended bitcoin withdrawal business , as they respond to China s central bank s call to strengthen anti-money laundry functions.

Huobi, OKCoin and BTC China issued announcements respectively in late Thursday, saying they would suspend the service of withdrawing bitcoin from the platforms.

They all said the measures were introduced according to the central bank requirements.

Conversion to and from the yuan is not affected and the curbs will be dropped after updates to compliance systems, the exchanges said.

Zhao Dong, owner of Jiandong Tech, a company that buys and sells bitcoin, said the new rule meant investors would be unable to transfer their holding of bitcoins back to their own purses.

To cash out, investors could only sell the bitcoins for yuan, as yuan withdrawal is still feasible on the platform -- this is a huge weigh on the bitcoin prices, he said.

The text above is a summary, you can read full article here.